rule target-source ( targets * : sources * : properties * )
{
}

actions target-source
{
    echo "NM target source consuming " $(>)
    echo "int main() {}" > $(<)      
}

rule cpp-mark ( targets * : sources * : properties * )
{
}

actions cpp-mark
{
    echo "CPP-MARK consuming " $(>)
    touch $(<)
}